UDF has to be compiled, can’t be interpolated Steps launch Fluent from the Command Line For ansys 16.x, launch Fluent from the Command Line using the VS2015 x86 x64 Cross Tools Command Prompt (not x64 x86 cross tools) 1) Open the Start screen (press Windows button on your keyboard, Type ' VS2013 x86 x64 Cross Tools Command Prompt ' 2) Navigate to your working folder, i.e. the folder where your case and data files are (.cas & .dat). 3) Type “fluent” in the command window to launch Fluent or “ C:\Program Files\ANSYS Inc\v161\fluent\ntbin\win64\ fluent.exe ” (quotation signs included, in case of standard installation; fluent version: 16.1). 4) Make sure that on the Environment tab 'Setup Compilation Environment for UDF' is ticked. The default address is fine. 1. Read mesh/cas file 2. Setup turbulence model/boundary conditions, etc. 3. Compilation a. Define/user-defined/functions/comp